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Results 301 - 350 of 825
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Chung F - - 1999
BACKGROUND AND PURPOSE: Understanding physiological responses to negative work allows therapists to be more knowledgeable when they prescribe this form of exercise. The physiological responses of 12 men without cardiopulmonary disease, aged 39 to 65 years (X=49.7, SD=9.3), to negative work (eccentric muscle contractions) and to positive work (concentric muscle ...
Lucía A - - 1999
The purpose of our investigation was to analyse the breathing patterns of professional cyclists during incremental exercise from submaximal to maximal intensities. A group of 11 elite amateur male road cyclists [E, mean age 23 (SD 2) years, peak oxygen uptake (VO2peak) 73.8 (SD 5.0) ml kg(-1) min(-1)] and 14 ...
Appendini L - - 1999
To investigate the physiologic effects of proportional assist ventilation (PAV) in difficult-to-wean, mechanically ventilated patients with advanced COPD, we measured in eight ICU patients the breathing pattern, neuromuscular drive (P0.1), lung mechanics, and inspiratory muscle effort (PTPdi and PTPpl) during both spontaneous breathing (SB) and ventilatory support with PAV, CPAP, ...
Prandi E - - 1999
Normal subjects can increase their capacity to sustain hyperpnoea by bracing their arms on fixed objects, a procedure which is also known to reduce dyspnoea in patients with chronic obstructive pulmonary disease (COPD). In the present study, it was tested whether bracing per se could improve the function of the ...
Bréchat P H - - 1999
Immersion is considered to facilitate exercise-based rehabilitation. However, the drag effect of moving limbs in water, likely to increase the respiratory requirements at exercise, is not mentioned in many reports. The energetic and ventilatory requirements of 30 min steady state cycling exercise performed by healthy male subjects in air and ...
McClaran S R - - 1999
We determined the role of expiratory flow limitation (EFL) on the ventilatory response to heavy exercise in six trained male cyclists [maximal O2 uptake = 65 +/- 8 (range 55-74) ml. kg-1. min-1] with normal lung function. Each subject completed four progressive cycle ergometer tests to exhaustion in random order: ...
Zakynthinos S - - 1999
We assessed the effects of two different expiratory maneuvers (fast [F] or slow [S]) on the ability of normal subjects (n = 12, age 35 +/- 6 yr) to generate maximal inspiratory pressures and maximal inspiratory flows near residual volume (RV). With the F maneuver, the subject exhaled rapidly to ...
Yan S - - 1999
To investiage the effect of inspiratory threshold load (ITL) on breathing, all previous work studied loads that were much greater than would be encountered under pathophysiological conditions. We hypothesized that mild ITL from 2.5 to 20 cmH2O is sufficient to modify control and sensation of breathing. The study was performed ...
Liebenberg C S - - 1999
The zero deadspace tracheal tube (ZEDS-TT) is a double-lumen endobronchial tube with a truncated bronchial limb. Functionally it is unrelated to the familiar endobronchial tube used in lung isolation surgery. It is placed in the same position as a regular tracheal tube and, by means of special connectors, one limb ...
Mota S - - 1999
In some trained athletes, maximal exercise ventilation is believed to be constrained by expiratory flow limitation (FL). Using the negative expiratory pressure method, we assessed whether FL was reached during a progressive maximal exercise test in 10 male competition cyclists. The cyclists reached an average maximal O2 consumption of 72 ...
Garcin M - - 1999
Perceived exertion has been investigated during incremental exercise to exhaustion with athletes, according to the 6-20 scale proposed by Borg (RPE, 1970) and a new scale based on the estimation of exhaustion time (t(lim)) (Estimated Time Limit or ETL, from 1 to 20; ETL= 21 - 2 n, with n ...
Gonzalez J - - 1999
Chest wall restriction, whether caused by disease or mechanical constraints such as protective outerwear, can cause decrements in pulmonary function and exercise capacity. However, the study of the oxygen cost associated with mechanical chest restriction has so far been purely qualitative. The previous paper in this series described a device ...
Scheuermann B W - - 1999
Breathing frequency (fb), tidal volume (VT), and respiratory timing during slow (SR, 8 W min-1) and fast (FR, 65 W min-1) ramp exercise to exhaustion on a cycle ergometer was examined in seven healthy male subjects. Expiratory ventilation (VE), pulmonary gas exchange (VO2 and VCO2) and end-tidal gas tensions (PET,O2 ...
Webster P A - - 1998
Our objective was to determine the validity of the SensorMedics 2900 Metabolic Measurement Cart (SensorMedics Corp., Yorba Linda, CA) for use at pediatric ventilator volumes by designing an in vitro validation study. The study was performed using a previously described nitrogen dilution, carbon dioxide infusion technique in which known amounts ...
Delpierre S - - 1998
Breathing through an inspiratory resistance induces a hypoventilation in mammals despite an increased diaphragmatic activity. We showed in previous works that an increase in GABA and endogenous opioid release in the central respiratory network could explain in part the inadequate increase in the inspiratory drive during inspiratory loading. In the ...
Das T K - - 1998
Volume and timing components of resting ventilation were measured serially in 40 women aged 18 to 36 yr, during menstrual, follicular and luteal phases of menstrual cycle. Resting minute ventilation (VE) was significantly higher (P < 0.001) in luteal phase than in menstrual and follicular phases; in the two latter ...
Tetzlaff K - - 1998
OBJECT: This study was carried out to evaluate changes in the breathing pattern of divers during exercise at an elevated ambient air pressure equivalent to a depth of 30 m of seawater. METHODS: A total of 22 healthy male subjects performed graded bicycle exercise in a dry hyperbaric chamber up ...
Ostlund A - - 1998
BACKGROUND: Increased inspiratory resistance in combination with mild gas narcosis is common during recovery after a general anesthesia, but there are only few previous studies on inspiratory loading during subanesthetic gas narcosis. METHODS: Responses of respiratory drive (central inspiratory activity, P0.1) and ventilatory pattern to an inspiratory threshold load of ...
Tejima T - - 1998
The late potential is useful to predict patients with sustained ventricular tachycardia (VT). However, because positive predictive value for sustained VT is low, the validity of late potential for screening the patients to be studied by electrophysiological tests was not high. We examined 923 cases, including 63 cases of sustained ...
Hagendorff A - - 1998
Arterial hypotension can cause cerebral ischemia when the autoregulation of the cerebral circulation is exhausted. We hypothesized that sudden cerebral vasoconstriction induced by moderate hypotensive, but hemodynamically stable, sustained ventricular tachycardias (MHT-VT) further compromises cerebral blood flow (CBF) and induces an ischemic stress response of the brain. CBF-measurements and morphological ...
Kobayashi H - - 1998
The amplitude of respiratory sinus arrhythmia (RSA) was measured in eight healthy young male students with special reference to the effect of tidal volume (Vt). Under simultaneously controlled respiratory frequency and Vt, the heart rate variability (HRV) of the subjects was measured. While the respiratory frequency was adjusted to either ...
Calabrese P - - 1998
In order to determine changes in breathing patterns brought about by resistive loading, ventilation was recorded in 11 healthy subjects with four linear resistances (3.57, 5.75, 8.76 and 13.13 cmH2O L(-1) sec) added in a random order throughout the entire breath. At steady state, a breath-by-breath analysis of airflow was ...
Johnson P H - - 1998
AIMS: To assess whether a domiciliary programme of specific inspiratory muscle training in stable chronic heart failure results in improvements in exercise tolerance or quality of life. METHODS AND RESULTS: We conducted a randomized controlled trial of 8 weeks of inspiratory muscle training in 18 patients with stable chronic heart ...
Brack T - - 1998
To examine the effect of resistive loading on variational activity of breathing, we studied 18 healthy subjects breathing at rest and with inspiratory resistive loads of 3 and 6 cm H2O/L/s, applied randomly for 1 h each. Compared with resting breathing, a resistive load of 3 cm H2O/L/s decreased the ...
Kapadia F - - 1998
There is presently considerable ambiguity and confusion relating to ventilator terminology. This can be eliminated using a simple approach, visualising mechanical ventilation as an inspiratory pump, and defining trigger, limit, and cycling in this context. The trigger is the signal that starts a breath by opening the inspiratory valve, the ...
McClaran S R - - 1998
We subjected 29 healthy young women (age: 27 +/- 1 yr) with a wide range of fitness levels [maximal oxygen uptake (VO2 max): 57 +/- 6 ml . kg-1 . min-1; 35-70 ml . kg-1 . min-1] to a progressive treadmill running test. Our subjects had significantly smaller lung volumes ...
O'Donnell D E - - 1998
We compared qualitative and quantitative aspects of perceived exertional dyspnea in patients with interstitial lung disease (ILD) and normal subjects and sought a physiological rationale for their differences. Twelve patients with ILD [forced vital capacity = 64 +/- 4 (SE) %predicted] and 12 age-matched normal subjects performed symptom-limited incremental cycle ...
Manecke G R GR Jr Department of Anesthesiology, University Medical Center, State University of New York at Stony Brook, 11794-8480, - - 1998
Although the esophageal stethoscope has been used for many years, the effect of the depth of placement on the quality of the sounds obtained has never been investigated. The amplitude and frequency characteristics of the first and second heart sound and of inspiratory and expiratory breath sounds were determined at ...
Melvin, William Stacy
(Abstract) <p>BACKGROUND. Previous research has shown that the ventilatory threshold (VT) correlates highly with onset of lactate accumulation and maximal steady-state exercise (MSS) level. Also, studies have shown the VT is useful in prescribing exercise for cardiac patients in that it gives an exercise intensity at which the patient is ...
Bittencourt L R - - 1998
The presence of abnormalities of the respiratory center in obstructive sleep apnea (OSA) patients and their correlation with polysomnographic data are still a matter of controversy. Moderately obese, sleep-deprived OSA patients presenting daytime hypersomnolence, with normocapnia and no clinical or spirometric evidence of pulmonary disease, were selected. We assessed the ...
Caretti D M - - 1998
The purpose of this study was to determine the effects of different inspiratory resistances on exercise performance and to describe physiological and subjective responses during constant load work of an intensity that elicits the maximum sensitivity to respiratory factors of respirator wear. Nine subjects (mean age 25.8 +/- 4.8 years) ...
Benumof J L - - 1998
The anesthetist will get the most information out of a capnograph if it is examined systematically. First, the anesthetist must determine whether exhaled CO2 (i.e., a waveform) is present. The differential diagnosis of absent CO2 includes esophageal intubation, accidental tracheal extubation, disconnection of the breathing circuit, complete obstruction of the ...
Feriche B - - 1998
BACKGROUND: The purpose of our investigation was to assess the use of a fixed value (12-13) of the Rating of Perceived Exertion (RPE) scale (6-20) as a valid method for the determination of the workload corresponding to the ventilatory threshold (VT) during a ramp protocol on a cycle ergometer. METHODS: ...
Rollier H - - 1998
The effects of 8 wk of inspiratory resistive loading (30 min/d, 3 x/wk) on diaphragm mass, contractile properties, fatigue, and fiber dimensions were studied in 10 male Wistar rats. They were conditioned to breathe through a Hans-Rudolph device. Half of them had to overcome a moderate inspiratory resistance (MR; n ...
Tantucci C - - 1998
The application of negative expiratory pressure (NEP) at end expiration has been shown to cause reflex-mediated activation of the genioglossus muscle in awake humans. To test whether a reflex contraction of pharyngeal dilator muscles also occurs in response to NEP applied in early expiration, the effect on genioglossus muscle reflex ...
McGregor H P - - 1998
In utero hypoxia may affect the development of the brain and result in altered respiratory responses postnatally. Using a barometric plethysmograph, we examined the effects of exposing pregnant guinea pigs to 200 ppm carbon monoxide (CO) for 10 h/d from d 23-25 of gestation until term (approximately 68 d) on ...
Mackey M - - 1998
BACKGROUND AND PURPOSE: Despite the arms being used extensively in the performance of many occupational tasks, little is known about the pattern of breathing and physiological cost of such work. The purpose of this study was to establish whether a simple change in arm support could alter the workload, pattern ...
Villafranca C - - 1998
There is very little information about the effect of inspiratory muscle training on inspiratory flow (V'I) and thus on power output (PO) in patients with chronic obstructive pulmonary disease (COPD). In this study we aimed to evaluate the changes induced by training on the determinants of PO. Thirty one patients ...
Prioux J - - 1997
The aim of this mixed cross-sectional longitudinal study covering a total age range of 11-17 years, i.e. the entire pubertal growth period, was (1) to specify the changes in maximal breathing pattern during incremental exercise; (2) to determine what parts of the changes are due to anthropometric characteristics, physical fitness ...
Yernault J C - - 1997
The forced expiratory manoeuvre was first described by Tiffeneau and Pinelli working in Paris (France), in December 1947, who proposed measurement of the "pulmonary capacity usable on exercise" (capacité pulmonaire utilisable à l'effort) (CPUE), the maximal volume expelled in one second after a deep inspiration. It was intended to replace ...
Aleksandrova N P - - 1997
The development of fatigue was investigated in the diaphragm of anaesthetized, tracheostomized, spontaneously breathing cats during restricted air flow. Ventilation, transdiaphragmatic pressure (Pdi), integrated electrical activity of diaphragm (Edi) and phrenic nerve (Eph) were measured simultaneously and expressed as a percentage of values at unloaded breathing. Inspiratory loads were 60, ...
Bocchi E A - - 1997
Multiple mechanisms have been proposed to explain the hyperventilation and the limited exercise capacity in congestive heart failure (CHF) including increased intrapulmonary pressures, total pulmonary resistance, and airway abnormalities. We investigated the hypothesis that inhalation of nitric oxide could influence the maximum exercise capacity and excessive ventilatory response to exercise ...
Brubaker P H - - 1997
STUDY OBJECTIVE: The purpose of this investigation was to compare multiple ventilatory responses of heart transplant patients (HTP) with normal subjects (NL) at rest, at absolute and relative submaximal exercise levels, and at peak exercise. DESIGN: Ten male HTP and 10 matched NL were tested under similar conditions on a ...
Mahon A D - - 1997
The purpose of this study was to examine blood lactate (BLa) levels and ratings of perceived exertion (RPE) in nine boys (10.5 +/- 0.7 yr) and nine men (25.3 +/- 2.0 yr) during exercise relative to ventilatory threshold (VT). VT and VO2max were determined during a graded exercise test on ...
Kenyon C M - - 1997
During exercise, large pleural, abdominal, and transdiaphragmatic pressure swings might produce substantial rib cage (RC) distortions. We used a three-compartment chest wall model (J. Appl. Physiol. 72: 1338-1347, 1992) to measure distortions of lung- and diaphragm-apposed RC compartments (RCp and RCa) along with pleural and abdominal pressures in five normal ...
Macdonald M - - 1997
We examined the hypothesis that O2 uptake (VO2) would change more rapidly at the onset of step work rate transitions in exercise with hyperoxic gas breathing and after prior high-intensity exercise. The kinetics of VO2 were determined from the mean response time (MRT; time to 63% of total change in ...
Yan S - - 1997
Inspiratory muscles are weak and contribute to exercise limitation in chronic obstructive pulmonary disease (COPD). Differential inspiratory pressure contributions from the diaphragm and inspiratory rib cage muscles (RCMs) during exercise in patients with COPD patients are insufficiently described. We measured, in 16 patients with COPD, the global inspiratory muscle pressure ...
Patrinos M E - - 1997
To investigate the role of high frequency oscillation (HFO) in promoting meconium clearance from the airway, we used a commercially available ventilator configured with maximal expiratory flow exceeding inspiratory flow (asymmetric HFO or AHFO). We hypothesized that AHFO would move meconium in an expiratory direction (toward the ventilator). We first ...
Road J D - - 1997
Phrenic motoneuron firing rates during brief inspiratory resistive loading (IRL) are high, and nearly all the motoneurons are recruited. Diaphragmatic fatigue has been difficult to demonstrate during IRL. Furthermore, evidence from studies in limb muscles has shown variable motoneuron responses to prolonged high-intensity loads. We studied phrenic motoneuron firing rates ...
Kayser B - - 1997
Nine healthy subjects (age 31 +/- 4 yr) exercised with and without expiratory-flow limitation (maximal flow approximately 1 l/s). We monitored flow, end-tidal PCO2, esophageal (Pes) and gastric pressures, changes in end-expiratory lung volume, and perception (sensation) of difficulty in breathing. Subjects cycled at increasing intensity (+25 W/30 s) until ...
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